Mental health bosses allowed Butler to live in the community, despite sectioning him three times.

He was convicted of manslaughter on the ground of diminished responsibility in 2005.

During his trial it was revealed that fear and loathing of the police were ‘at the core’ of his mental illness – but no note of his delusions was made on his health files.

And following his trial a catalogue of fatal healthcare blunders was reported.

These included an incident just a month before Michael was killed, when a psychiatrist spotted a large knife on Butler’s sofa and gouge marks on a door.

Amazingly, the health worker concluded that the mental patient’s explanation that they were caused by his martial arts training ‘was not unusual’.

NHS West Midlands promised to conduct an inquiry into the failings, but the official report has yet to be released.

“At first I felt really angry towards Butler,” admits Carol. “But at the trial it was so obvious that he was mentally ill. It was a very strange feeling and I just blanked it all out.

“Still, I am glad that he will never be released from the secure unit.

“At the time I was more annoyed with the mental health trust. How could they have found a knife and not done anything about it?

Slowly but surely Carol and the couple’s daughter Kelly, 21, started to rebuild their lives.

And Carol reveals her new love Neil Tyers, 33, from Uttoxeter, Staffordshire, helped to play a vital role helping her to learn how to deal with the tragedy.

“When Michael died it just seemed so unreal,” she recalls. “I didn’t believe it. I was just in this strange state. “I never believed that anything like this would happen, even though he worked as a policeman.

“Michael was in the Army before he went on to join the police force. I never really thought about his job being dangerous. When he talked about work to me, there was never anything to be alarmed about.

“Luckily, I have a very big family around me and they supported me throughout.

“I found that other people just didn’t know what to say to me. But that’s where Neil was so different.

“He would call me up and talk to me about Michael, and I could speak to him about it.”

Carol met Neil through work.

She worked in the transport department of a local company while Neil worked in the warehouse. Although the couple never worked together closely, they still enjoyed friendly banter.

Ironically, their romance mirrors the way Carol had met Michael 23 years ago.

Both were working at a car show salesroom when they began dating.

“I was working in the offices when Michael started as a salesman there,” says Carol. “He was hopeless though, and only sold one car in the year he was there.

“But he did manage to ask me out.”

The couple dated for four years before they eventually tied the knot. Two years later, daughter Kelly was born.

Although Carol has known Neil for six years it wasn’t until last year that the couple got together.

She left work two years ago and continued her friendship with Neil. When she returned from holiday in Mexico with her sister, they began to see more of each other.

“Neil called me and we decided to go out for a drink,” she recalls. “Things developed from there really.

“I felt really comfortable with him because I’d known him for years. He has got a great sense of humour.

“I certainly never thought that I would meet anyone else. After Michael’s death I didn’t have a relationship with anyone, although there was hope that someone else would come along in the long run.”

Although Carol hopes to marry Neil, the couple are yet to be engaged.

“Neil hasn’t asked me yet, but we are hoping to get married next year,” she says.

Carol has put the home she shared with Michael up for sale and plans to move closer to Neil’s house in Uttoxeter, Staffordshire.

“I’ve been in this house for 11 years,” she explains. “If I can sell it, I will move closer to Neil. Then we’ll see how things continue.

“Kelly gets on with him really well. And I know that if Michael had known him, he would have really liked him. They never met even though I knew Neil when Michael was alive.”

Earlier this month the pair both attended a ceremony to unveil a memorial to Michael on the spot where he was killed.

The service was opened by film director and chairman of the Police Memorial Trust Michael Winner, who said: “You could rewrite the dictionary and write under H for Hero ‘to act like Michael Swindells’.”

Kelly paid tribute to her dad at the ceremony, too.

“He wasn’t just a dad,” she said. “He was a great dad, and I know he was a great husband to my mother, too. ”